Years ago we had a long haired Chihuahua, he started to swell up the vet said he had kidney problems. He was also urinating everywhere and it a lot of blood in it. He was about 12 years old, he lived with us for about 4 years after someone dumped him off on our road. We were happy we were able to give him a peaceful life in his remaining years.
And the dog we had when I was a child had the same problem he was around 16 when he passed on.